Composition for cleaning photographic equipment

ABSTRACT

An acidic aqueous cleaning solution for removing deposits from photographic equipment, especially continuous processing photographic equipment. The composition comprises a solution and preferably an aqueous solution of hydrogen ions in a concentration of from 0.10 to 8.0 moles per liter, ammonium ions in a concentration of from 0.01 to 1.0 moles per liter, and sulfate ions in a concentration of from 0.10 to 6.0 moles per liter. The compositions of this invention are especially useful for removing deposits from continuous diffusion transfer processing equipment. These deposits possibly comprise lime introduced with tap water mixed with photographic chemicals such as dissolved silver halides and gelatin.

unucu Dl'dlCB rulcul Inventor Irving .1. Magin Rochester, N.Y.

Appl. No. 739,173

Filed June 24, 1968 Patented Dec. 7, 1971 Assignee ltelt Corporation Lexington, Mas.

COMPOSITION FOR CLEANING PHOTOGRAPHIC [56] References Cited UNITED STATES PATENTS 2,878,189 3/1959 Certa 134/41 X 3,449,164 6/1969 Vinkler et a1. 134/41 X Primary Examiner-Mayer Weinblatt Arromeys Homer 0. Blair, Robert L. Nathans and W. Gary Goodson ABSTRACT: An acidic aqueous cleaning solution for removing deposits from photographic equipment, especially continuous processing photographic equipment. The composition comprises a solution and preferably an aqueous solution of hydrogen ions in a concentration of from 0.10 to 8.0 moles per liter, ammonium ions in a concentration of from 0.01 to 1.0 moles per liter, and sulfate ions in a concentration of from 0.10 to 6.0 moles per liter. The compositions of this invention are especially useful for removing deposits from continuous diffusion transfer processing equipment. These deposits possibly comprise lime introduced with tap water mixed with photographic chemicals such as dissolved silver halides and gelatin.

COMPOSITION FOR CLEANING PHOTOGRAPI-IIC EQUIPMENT BACKGROUND OF THE INVENTION 1. Field of the Invention An acidic aqueous cleaning solution especially useful for removing deposits from the surfaces of continuous processing photographic equipment.

2. Description of the Prior Art It is known that in the course of photographic processing, dark-colored deposits frequently form on photographic processing equipment. It is believed that these deposits are essentially lime derived from hard water mixed with various photographic chemicals such as dissolved silver halides. It is also known that these deposits are readily removed from the processing equipment by rinsing with a simple acid cleaning solution. For example, one cleaner commercially available comprises an aqueous solution of sulfuric acid and sodium bichromate. Another cleaner involves the sequential use of two solutions; the first comprising a mixture of potassium bichromate and sulfuric acid and the second comprising a mixture of potassium permanganate and sulfuric acid.

The above-noted cleaning solutions are suitable for cleaning processing equipment having deposits of the above description. However, where continuous processing equipment is used, and contact with the equipment is over an extended period of time, the deposits become heavy. Where diffusion transfer processes are used, the problem becomes more acute because unexposed portions of a gelatin layer are dissolved from the photographic emulsion. The gelatin is believed to comprise a portion of the deposit, possibly codeposited with line and other photographic processing chemicals. Deposits of this nature on continuous diffusion transfer processing equipment are extremely difficult to remove and prior art cleaning solutions have been found to be inadequate.

STATEMENT OF THE INVENTION The present invention provides a cleaning solution capable of removing heavy deposits from photographic processing equipment and is especially useful for cleaning continuous diffusion transfer processing equipment. The cleaning solution is an acidic aqueous solution comprising hydrogen ions in a concentration of from 0.10 to 8.0 moles per liter, sulfate ions in a concentration of from 0.10 to 6.0 moles per liter and ammonium ions in concentration of 0.01 to 1.0 moles per liter. The composition is derived from the corresponding acids and salts of the respective ions in solution and preferably from sulfuric acid, ferric ammonium sulfate and water.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Sulfuric acid is the preferred source of both the hydrogen ions and sulfate ions. However, other acids such as hydrochloric acid, nitric acid, hydrofluoric acid, phosphoric acid, citric acid and the like may be used in combination with a metal salt of sulfuric acid such as sodium sulfate, potassium sulfate. calcium sulfate, ferrous sulfate, aluminum sulfate, magnesium sulfate, ammonium aluminum sulfate, ammonium cerium sulfate, barium sulfate, cadmium sulfate, cerium sulfate, chromium sulfate, lead sulfate, magnesium sulfate, manganese sulfate, mercuric sulfate, mercuric ammonium sulfate, potassium cobaltous sulfate, potassium iron sulfate, potassium magnesium sulfate and the like.

The ammonium ions may be derived from an aqueous ammoniacal solution or an ammonium salt such as ammonium aluminum sulfate, ammonium bromate, ammonium cadmium chloride, ammonium calcium arsenate, ammonium carbonate, ammonium cerium sulfate, ammonium chromate, ammonium chromium sulfate, ammonium copper chloride, ammonium fericyanide. ammonium chloride, ammonium iodide, ammonium iron sulfate, ammonium magnesium carbonate, ammonium magnesium sulfate, ammonium molybdate, ammonium nitrite, ammonium propionate, ammonium selenate, ammonium sulfide, ammonium zinc sulfate and the like. The ammonium metal sulfates are preferred and the most preferred ammonium salt is ferric ammonium sulfate. The function of the ammonium ions is not fully understood but is believed to assist in the dissolution of silver salts through complex formation.

Preferably, the concentration of hydrogen ions varies between 0.10 and 8.0 moles per liter, the concentration of sulfate ions varies between 0.10 and 6.0 moles per liter and the concentration of the ammonium ions varies between 0.01 and 1.0 moles per liter. A preferred composition is as follows:

TABLE I H 1.0-3.0 moles/liter SO." 0.5-2.0 moles/liter NH. 0.05412 moles/liter The preferred composition for forming the cleaning solution of this invention is as follows:

TABLE 2 H,SO,(97.2 '5) 10-250 ml. Fem-M50 1 214,0 10-250 g. Water to 1 liter Parts from photographic equipment are cleaned by immersion in the cleaning solution of this invention for a time sufficient to loosen the deposits. Preferably, the cleaning solution is agitated during immersion. This time is dependent upon the strength of the cleaning solution and the nature and thickness of the deposit to be removed. In general, the time may vary between a few minutes to a few days. Following immersion of the part in the cleaning solution, the loosened deposit is removed, preferably by wiping with a wet or damp cloth and the part is washed with water. Caution should be exercised in using the cleaning solution of this invention as it is strongly acidic and may cause damage to metallic surfaces readily attacked by strong acids.

The invention, above disclosed, is exemplified as follows EXAMPLE I H,S0.(97.2 5) 50 m1. FeNH,(SO,),- 12H,O 50 Water to 1 liter A rack having a multiplicity of stainless steel rollers and two polyvinyl chloride rollers was removed from a continuous processing apparatus used for diffusion transfer processing. The apparatus had been in continuous use for approximately hours. Portions of the surface of the rollers were coated with a heavy gray-black hard deposit. The above cleaning solution was agitated and the rack immersed in the solution for approximately ten minutes, removed and wiped with a damp cloth to remove all loose deposits on the surface of the rollers. Following a water rinse, it was observed that the roller surfaces were clean and free of all deposits.

EXAMPLE 2 H,so, 91.2 s 20 ml. FeHH,(SO.), l21-l,tl 20 Water [0 1 liter The procedure of example 1 was repeated with immersion in the cleaning solution for approximately 4 hours. All of the deposit was removed from the surface of the rollers. The extended period of four hours was required due to the low acidity of the solutions.

EXAMPLE 3 ",NO,( 70.7 percent) 50 ml. FENH4(SQ)|'I2H1O 50 Water to 1 liter THe procedure of example 1 was repeated with immersion in the cleaning solution for approximately 3 hours. Most of the deposit was removed from the roller surfaces following wiping with a damp cloth.

EXAMPLE 4 Citric acid 50 g. FeNHA SO, l 2H,O 50 Water to 1 liter The procedure of example 1 was repeated with immersion of the rack in the cleaning solution for approximately 4 hours. Most of the deposit was removed from the surface of the rollers following wiping with a damp cloth.

EXAMPLE 5 A prior art commercially available cleaning solution believed to have the following composition, was substituted for the formulation of example 1.

Sulfuric acid 90 ml. Potassium biehromate 90 Water to l liter Following the procedures of example 1, the rack was immersed in the solution for approximately l0 hours. Upon removal and examination of the rack, heavy deposit was observed on the surfaces of the rollers.

The above examples have been presented for the purpose of illustration and should not be taken to limit the scope of the present invention. lt will be apparent that the described examples are capable of many variations and modifications which are likewise to be included within the scope of the present invention as set forth in the appended claims.

I claim:

1. A composition for cleaning photographic equipment consisting essentially of an aqueous solution of a combination of at least one acid and at least one other ingredient, all of the ingredients in said combination contributing to yield in said solution hydrogen ions in a concentration of from about 0.10 to about 8.0 moles per liter of solution, ammonium ions in a concentration of from about 0.01 to about 1.0 moles per liter of solution and sulfate ions in a concentration of from about 0.10 to about 6.0 moles per liter of solution.

2. The cleaning composition of claim 1 wherein said combination contributes to yieldvin said solution hydrogen ions in a concentration of from about 1.0 to about 3.0 moles per liter. ammonium ions in a concentration of from about 0.05 to about 0.2 moles per liter and sulfate ions in a concentration of from about 0.50 to about 2.0 moles per liter.

3. The cleaning composition of claim 2 where the source of the hydrogen ion is an acid.

4. The cleaning composition of claim 3 where the acid is sulfuric acid.

5. The cleaning composition of claim 4 where the source of the ammonium ions is an ammonium salt.

6. The cleaning composition of claim 5 where the ammonium salt is ferric ammonium sulfate.

7. The cleaning composition of claim 1 having the following formulation:

n,so. 97.2 10-250 ml. FeNH (SO ),-I2H,O l0-250 g. Water to l liter of solution.

8. Tile cleaning composition of claim 1 having the following formulation:

H,SO (97.2 '1') about 50 ml. FcNHJSO l2H,O about 50 Water to l liter of solution 

2. The cleaning composition of claim 1 wherein said combination contributes to yield in said solution hydrogen ions in a concentration of from about 1.0 to about 3.0 moles per liter, ammonium ions in a concentration of from about 0.05 to about 0.2 moles per liter and sulfate ions in a concentration of from about 0.50 to about 2.0 moles per liter.
 3. The cleaning composition of claim 2 where the source of the hydrogen ion is an acid.
 4. The cleaning composition of claim 3 where the acid is sulfuric acid.
 5. The cleaning composition of claim 4 where the source of the ammonium ions is an ammonium salt.
 6. The cleaning composition of claim 5 where the ammonium salt is ferric ammonium sulfate.
 7. The cleaning composition of claim 1 having the following formulation: H2SO4(97.2 %) 10- 250 ml. FeNH4(SO4)2.12H2O 10- 250 g. Water to 1 liter of solution.
 8. The cleaning composition of claim 1 having the following formulation: H2SO4(97.2 %) about 50 ml. FeNH4(SO4)2.12H2O about 50 g. Water to 1 liter of solution 